Security plugins? What ones are Needed?

I just installed wp db manager, antivirus, bullettproof security, and login lockdown, along with site maintenance how many plugin do I need to protect my site?

I tryed bullettproof, put it into maintenance mode and wasn’t able to get back to admin site to sign in. I tryed to delete that plugin via ftp and still was locked out. I heard something about renaming the htaccess file that didnt work, so I finally just did a new install of wp, along with config file and uploaded my previous xml file and got backup.

I figured the antivirus,login lockdown and db maintenance are probably important, but does anybody have any recommendation for securing your database or a good plugin that prevents anytypes of hacks.

Thanks